Pump



May 13# 1947- A. v. Mur-:LLr-:R 2,420,556

4 PUMP Filed Nov. 24, 1945 5 Sheets-Sheet l May 13, 1947'.

A. V. MUELLER PUMP Filed NOV. 24, 1943 3 Sheets-Sheet 2 INVENTOR. wwwNamen Y @la money! May 13, 1947.

A. V. MUELLER PUMP Filed Nov.- 24, '1943 3 Sheets-Sheet 3 IN VEN TOR.

ALB/mNof/Y M/Iafufn feb/f '.v 7155 Patented May 13, 1947 PUMP AlexanderV. Mueller, Salem, Ohio, assigner to The Deming Company, Salem, Ohio, acorporation of Ohio Application November 24, 1943, serial No. 511,577

(cl. s- 96) 31 Claims.

This invention relates to, a rotary pump of the type having an impellerbetween two heads which are in close proximity to the faces of theimpeller, and anobject of the invention is to provide means forincreasing the efficiency of such a pump by preventing or greatlyreducing leakage between the heads and impeller.

More particularly, the invention relates to an;

impeller pump having a rotary impeller with an annular row of vanes orbuckets adjacent its periphery, such impeller being mounted between twoframe members which stand adjacent the impeller and one or both of whichcooperate with the buckets andI extend across the periphery of theimpeller and carry an annular water passageway with which spaced intakeand discharge passages communicate. In pumps of this type it has beencustomary to make the frame members or stationary heads stand very closeto the face of theimpeller, while out of contact therewith, and hencethere has been always some leakage between the faces of the impeller-andthe heads, reducing the efficiency of the pump. Furthermore, thisleakage water frequently carries grit4 with it which scores the faces ofthe'impeller and progressively diminishes its effective operation.

My invention provides pressure seals having annular faces which aremaintained in actual contact with the faces of the impeller bycontinuous pressure, with the result that the' leakage and consequentscoring is practically eliminated.

My invention provides also means to prevent leakage between the pressureseals and the stationary frame members in which they are mounted.Accordingly, leakage is prevented around the exterior of the seals, asWell as between them and the impeller. These features have a furtheradvantage of avoiding the requirement for stuiiing boxes about the shaftto prevent leakage from thepump. f Y

IMy invention 'is hereinafter more fully expl-ained in connection withpreferred embodiments thereof, illustrated in the drawings, and theessential novel features are summarized in the claims.

In the drawings, Fig. 1 is peller, the plane ofl the section beingindicated f by the line Sf-3 on Fig. 1; Fig. i is a fragmentary radialsection through a portion ofthe impeller averticai axialV sec- `tionthrough one embodiment of my impeller and the cut-water or stop-blockbetween the intake and exit passages, as indicated by the linel 4--4 onFig. 2; Fig. 5 is a perspective of the cutwater block detached andinverted; Fig. 6is-a vertical axial section (partly broken away) througha modified formof pump having my invention.

It will be convenient to describe first the general construction of thepump illustrated in Figs.

1 and 2, before taking up the features constitut- J.

ing my invention. It should be understood, however, that the inventionis not coni-ined to the pump construction illustrated.

In the form shown in Fig.'1, the frame of the pump comprises a verticalring-like member I0 having a suitable base portion II and carrying atthe top a hollow discharge chamber I2, which may be integral with thering of the frame or attached thereto. This view shows two end membersI3 and I4 which abut the sides of the frame ring I0 and are securedthereto, 4cap screws 20, passing through flanges I5 and I6 on the endmembers, being shown for this purpose. Each of the frame members I3 andI4 is shown as cupshaped and formed at its central region into a sleeveportion I1 and I8 carrying a bearing for the shaft; suitable ballbearings 23 and 24 being shown in the drawing. n

30 indicates the driving shaft of the pump which is mounted in the twobearings 23 and 24. This shaft carries the impeller 40 which coacts withmembers to-be described. The impeller is shown as keyed at 4I to theshaft and longitudinally positioned by being mounted between a pair ofsleeves 32 on the shaftI which are forced against the impeller by nuts33 screwing onto threaded portions 34 on the shaft. This makes a simpleconstruction rigidly securing the impeller to the shaft in the desiredposition while enabling ready installation of the impeller on the shaftor its frame portion I8 across the other end of the shaft.

` The impeller 40 is of a general disc form, and carries an annular rowofbuckets` adjacent its periphery. The actual form or direction of thebuckets may Yvary and they kmaybe on one or both sides of the impeller,as desired. I have shown buckets made by radial notches 42 in voppositesides of the impeller, the notches on veither side leaving betweenradial vanes 43. i

These vanes'operate in` an annular passageway provided by two stationaryheads or frame members 50. These heads are mounted within the frame ringI and abut eachother at their inner faces. 'I'hey are shown as abuttedat their outer faces by the ends of the frame members I3 and I4. Theseheads therefor when the pump is assembled constitute part of thestationary frame of the pump.

The frame member I3 may be bolted snug without gaskets against the ringI0, but I prefer to employ a gasket (indicated at 28 in Fig. 1) betweenthe flange of the frame member I4v and the central ring member, as thatis the frame member which would be removed to obtain access to the pump.

The heads 50 are symmetrical, each formed with smooth nearly annularfaces 5I adjacent its periphery, which faces abut each other tightly.Within the nearly annular regions 5I, and opposite the buckets 42 andbeyond the periphery of the impeller, in the form shown, are formedgrooves 52 which coact to make the annular passageway in which thebuckets travel. 'I'his annular passagewayleads from an intake passage 54communicating with the suction or supply chamber 55 of the pump. Anothernearly radial passageway 56 leads from the annular raceway 52 to thedischarge port 51 in the frame ring and thence to the discharge chamberI2.

Between the intake or suction passage 54 and the discharge passage 51 ismounted the socalled cut-water separating these passages. This maycomprise a bifurcated block 60 (Figs. 2, 4 and 5) occupying the racewayin this location and straddling the-impeller and thus blocking thepassage of liquid about the impeller -buckets from the discharge passageto the intake passage, except such small amount as may be carried by the`buckets 42 themselves moving past the block.

I have given above a description of the particular pump illustrated inFigs. 1 and 2 of the drawings in order that the application and functionof the sealing means constituting my .nvention about to be described maybe better understood. Such sealing means, however, is capable of a widevariety .of applications to impeller pumps differing materially fromthat above specifically described.

Heretofore in impeller pumps such as above described it has beencustomary to extend the stationary heads 50 inwardly close to the faceof the impeller and continue them into a region near 'the shaft, wherethey have been provided with external stuilng boxes preventing dischargeof the water which necessarily leaked inward between the impeller andsuch stationary heads. In my invention, however, I eliminate the leakageand the necessity of the stufilng boxes by a novel construction at thesides ofthe impeller, which I will now describe.

I provide each vframe head 50 with a cylindrical bore, which may be ofsubstantially the same diameter as* that of the impeller body betweendiametrically opposite vanes, and in these two circular openings I mounttwo annular pressure heads or seals which fit slidably in the bores andhave smooth inner faces contacting with the faces of the impeller. Eachof these heads is pressed into actual contact with the impeller andconstantly maintained in such contact.

To effect thc pressure of the heads or seals 10 against the impeller, Iprovide a pair of yielding pressure devices acting against the outerfaces of the seals. I have shown, for this purpose, a pair of helicalcompression springs 80 whichbear 4 at their inner ends against therespective pressure heads and at their outer ends against abutmentscarried by the frame, for instance, webs I9 on the frame members I3 andI4.

of the coil spring to expand.

'I'he two pressure heads may be of hardened metal or other wearresisting material and have their inner faces polished or lapped in soas to be very smooth and in contact directly with the smooth face of theimpeller, which is preferably of bronze. In such construction there isno annular space between the inner faces of these pressure seals and thefaces of the impeller and, hence, no leakage about the impeller facefrom a region of higher pressure to a region of lower pressure.

To prevent leakage of the pumped liquid from the annular raceway acrossthe outer perimeter of the pressure heads I provide suitable packingrings 90 which seat in grooves in the respective seal rings and coactwith the frame heads 50. The packing rings may be of any suitablematerial. If of rubber, they may well extend radially beyond the bore ofthe frame members 50 and coact with the inner faces thereof, as shown inFig. 1. Where the :packing rings cross the cutwater block 60 they occupyrabbets 62 formed in the block, as illustrated in Figs. 4 and 5.

The sealing rings may be of such material, or have such inner faces,that no lubrication between them and the impeller is necessary. However,I have made provision for supplying lubricant to these faces. Thus. asshown in Fig. 1, I have provided oil passages 15 in the pressure heads,shown as communicating with passages 58 in the frame heads, which lattercommunicate with oil passages 26 in the central frame member at the baseof the discharge chamber I2. The latter passages preferably extendinwardly diagonally and carry internal threads 21 for the application ofny suitable oiling coupling. By this means, I can readily supplylubricant to the faces of the impeller in the region of its engagementwith the pressure heads.

The heads 50 in one region may have lugs 59 occupying recesses in thepressure heads to prevent any circumferential displacement of the heads,so that communication of the lubricating passages 15 and 58 is assured.

In Fig. 6, I have illustrated another embodiment of my invention whereinthe pump casing. the shaft carried thereby and the impeller and liquidpassageways are similar to those already described, but wherein thestationary frame heads and sealing means they carry are specicallydifferent through operating in the same general manner as in the firstembodiment.

In Fig. 6, 90 indicates the ring-like central frame with its dischargechamber 9i 92 and 93 indicate the side frame members; 94, the shaftheads |00 seat within the ring Opening of the v frame 90 and abut eachother on their inner 92 and' 93. The stationary frame members |00.however, specifically differ from tl'.: corresponding members 50 of thefirst embodiment, as will now be described.

Each of the frame members ,I00, while having the same inner .face ashereafter described, has

on its outer side an annular projecting portion to the outer face ofwhich is secured a stationary frame ring |05. lThis maybe attached tothe annular extension by cap screws |00. Threaded within the plate is anexternally threaded sleeve I I0. The inner end of this sleeve abuts aring |20 which hasa cylindrical flange |2| loosely surrounding theshaft. The spring bellows I 25 constructed as heretofore described,surrounds this flange I2I and bears at its outerend against the threadedsleeve |I0, indirectly through the ring |20, and at its inner endagainst the annular sealing"` head |30, the inner face of which coacts'with the side of the impeller after the manner of ment. i Y

The threaded abutment sleeve I0 and the ring |20 furnish means foradjusting the compression of the spring bellows |25 to adjust thepressure of the seal against the impeller. The flange |2| on the ring|20 does away. with the possibility of the rubber spool of the springbellows contacting with the rotating shaft and being worn thereby.

The spring sleeve I |0 is intended to have its threads fit withsufficient snugness so that it will remain in place without thenecessity of a jam nut, and this sleeve nut accordingly furnisheseffective means for adjusting and maintaining the desired pressure ofthe sealing ring against the impeller. There is a clearance space |3| atthe inner periphery of the seal ring sufficient to receive thecylindrical flange |2I, so that a considerable adjustment of the springbellows is permissible.

' In either `embodiment illustrated. due to they the ring 10 in thefirst embodi- 6 any other location about the axis of the shaft. as willbe readily understood.

smoothA engaging surfaces of the impeller and the sealing pressureheads, and the lubricant if employed, there is very little actualfriction between the rubbing surfaces, and the wear is negligible,though the heads are constantly maintained in liquid tight. engagementwith the impeller. As the pressure heads are self sealing. there isvpractically no leakage along the face of the impeller from any regionof higher pressure to one of lower pressure and the emciency is thusincreased, and the troublesome scoring which has taken place in the pastis eliminated. The efliciency is further increased by the annularpacking, preventing leakage about the exterior of the seals. As theleakage is prevented both along the impeller face and also along theouter periphery of the pressure heads, I do away with the necessity ofstufllng boxes coactingwithy the ports. In such a pump the pressure ispractically The packing between the seal rings and the the wall of thebore of theeframe member |00 which is occupied by the sealing ring`after the manner of a piston in a cylinder. However, I prefer to allowclearance, indicated at |02 about the seal-head periphery, so that theface ofthe seal head may automatically adapt itself tothat of theimpeller without requiring the maximum accuracy in the bbre of the framehead.

The lubricating means illustrated in Fig. 6 is also specificallydifferent from that heretofore described.. These comprise merelydiagonal paslow pressure region. This loss cannot be avoided,`

sageways |50 through the annular extensions |0| on the frame members|00. Such passageways may terminate at their outer ends in internallythreaded portionsforthe application of suitable nipples. Lubricantinserted through these passageways may if desired fill the annularspaces about the exterior of the spring seals. Suitable passageways |35through the seal heads them` selves may convey lubricant from suchannular spaces to the faces of the seal rings. For convenience ofillustration diagonal passageways |50 are shown in the plane in `whichthe section of Fig. 6 is taken, though such openings may be in zero atthe intake and the pressure builds up gradually around the periphery ofthe impeller, reaching a maximum at the discharge. Hence, at everyregion of the periphery of the propeller, there is a tendency of liquidto pass via the flat side of the impeller from every region about theimpeller (except the region which happens to be at the intake opening)to other regions where the pressure is lower. In the ordinary pump ofthis type. the heads are made to stand as close as practicable to thesides of the impeller and still .leave sufficient clearance to preventcontact,

and hence, au` around the impeller liquid will be forced by the built-uppressure into the annular space at the sides of the-impeller and thenceinto the intake passageway where the pressure is lowest. Thislossmaterially reduces the emciency of the pump.

Of course, there is necessarily some leakage fromthe discharge port tothe intake port, by the buckets themselves as they pass through theseparator, from the high pressure region to the but by itself is nottroublesome. It is when there is added to this loss,.the loss all aroundthe imheller through the clearance spaces at the sides thereof. that theaggregate' loss materially reducesthe efficiency. My invention ofthepressure seals in actualcontact with the sides of the impeller, and withprovision for preventing leakage at the outer periphery of the seals,`eliminates all of this additional loss. Y

I claim:A -11. In av pump, the combination of a rotary shaft,` animpeller thereon having an annular Y -row of vanes adjacent-itsperiphery. means cle- 'iining a passageway in which the vanes travel,ajmovable sealing ring surrounding the shaft,

means for. yieldingly pressing such sealing ring into contact with theside ofthe impeller,4 and an annularmember coacting with, the ringpreventing leakage fromsaid passageway across the /periphery of saidring. a 2. In a pump, the combination of a rotary impeller having anannular row of vanes and having smooth faces on its opposite-sidesbetween the vanes and the axis, means defining a passageway in which thevanes travel with intake and exit passages to and from said passageway,a pair of movable pressure heads engaging said smooth faces of theimpeller, and means for'maintaining said heads in such engagement.

3. In a pump, the combination of a rotary impeller having parallel fiatfaces on its opposite sides and carrying a row of laterally open bucketsbeyond said faces, means defining an annular passageway in which saidbuckets travel, intake lfand exi-t passages communicating lwith saidannular passageway, a pair of sealing rings having :dat inner surfacescontacting with the sides of the impeller, and a pair of pressuredevices acting on the respective rings to maintain said rings in contactunder pressure against the opposite faces of the impeller.

4. In a pump, the combination of a rotary impeller having faces on itsopposite sides and carrying a row of buckets beyond said faces, meansdefining an annular passageway in which ,said buckets travel, intake andexit passages communicating with said annular passageway, a pair ofheads having smooth inner surfaces automatically pressed into contactwith the sides of the impeller, and a pair of yielding annular memberspreventing leakage across the perimeter of the respective heads.

5. In a pump, the combination of a rotary drive shaft and an impellerthereon having a smooth side face and an annular row of buckets entirelybeyond said face, stationary means deiinng an annular passageway inwhich the buckets travel, intake and exit passages communicatingdirectly with said passageway, a sealing ring engaging said smooth facevof the impeller close to the inner periphery of the buckets, and aspring surrounding the shaft and compressed respective- 1y between saidring and a stationary abutment,

'whereby said ring is maintained in snug engagement with the side faceof the impeller.

6. In a pump, the combination of a rotary drive shaft and an impellerthereon having lrow of buckets beyond said faces, a pair of stationaryheads of annular form having mating grooves to provide a passageway'about said buckets and intake and'exit passages to and from saidpassageway, and a pair of movable pressure heads mounted within thestationary heads and surrounding the shaft and contacting with theopposite faces of the impeller, and yielding means` for maintaining themovable heads pressed. against the impeller.

9. In a pump, the combination with a frame'Y a shaft carried thereby, animpeller on the shaft having fiat sides with an annular row of bucketsbeyond said at sides, a pair of stationary abutting heads in annularform on opposite sides of the impeller, said heads being recessed todene a passageway extending about the impeller buckets and on each sidethereof and beyond the periphery of the impeller, said heads having alsooutwardly extending notches to define intake and discharge passages,there being means separating said passages beyond the periphery of theimpeller, a pair of annular pressure heads surrounding the shaft andmounted within openings in the stationary heads and engaging oppositesides of the impeller, and spring means acting on said pressure heads icmaintain the heads in snug engagement with the sides of the impeller.

10. In a pump, the combination of an impeller having an annular row ofbuckets adjacent its periphery and having smooth faces between thebuckets and axis, stationary means defining a- Y passageway occupied bythe buckets with intake smooth faces on its opposite sides and anannular row of buckets beyond said faces, stationary means dening anannular passageway in which the vanes travel, intake and exit passagescommunicating directly with said passageway, means for blocking thespace between the intake and exit passages beyond the periphery and atthe sides of the impeller buckets, and a pair of movably mounted headsengaging opposite faces of the impeller, and a pair ofspringssurrounding the shaft and compressed respectively between one of saidheads and stationary abutments, whereby said heads are maintained Iinsnug engagement with the sides of the impeller.

7. In a pump, the combination of a pair of frame members in faceabutment providing an annular passageway with intake and exit ports, arotary impeller mounted at the axis of said annular passageway andhaving an annular row 1 of buckets in said passageway and a smooth facebetween the buckets and axis, a pressure head slidably mounted withinone of said frame members and having a smooth inner face engaging saidsmooth face of the impeller, and yielding means acting on the pressurehead to maintain such engagement.

8. 'In a pump of the character described, the combination of a shaft, animpeller thereon having smooth opposite side faces and an annular anddischarge passages to and from said passageway, said means havingopenings about the axis of the impeller, a pair of pressure headsmounted in said openings 0n opposite sides of the impeller, spring meansfor maintaining the pressure heads in contact with the smooth faces ofthe impeller, and annular yielding members closing the spaces betweenthe perimeter of the pressure heads and the openings in the stationarymeans which they occupy.

11. In a pump, the combination of a frame, a pair of coacting stationaryheads carried thereby having aligned cylindrical openings, said headsproviding an annular passageway beyond said openings with intake anddischarge passages leading to the exterior, a shaft coaxial with saidcylindrical openings, an impeller on said shaft having an annular row oflaterally open buckets in said annular passageway, said annularpassageway being interrupted beyond the periphery of the impeller and atthe sides of the buckets between the intake and discharge passages, apair of pressure heads slidably mounted in the cylindrical openings ofsaid stationary heads and abutting the opposite faces of the impeller,springs for maintaining the pressureheads in snug contact with theimpeller, and an annular packing between lthe pressure rings and saidstationary heads to prevent leakage from the annular passageway acrossthe outer perimeter of the pressure heads.

12. In a pump, the combination of a rotary shaft, an impeller mountedthereon and having smooth opposite faces and an annular row of bucketsbeyond the faces, a pair of annular frame members on opposite sides ofthe impeller having mating annular grooves to provide a raceway for theimpeller buckets. admission and discharge passages leading from saidraceway to the region beyond the perimeter of said annular framemembers, means carried by the latter separating the admission anddischarge passages, a pair of anmaar pressure heads slidably momieseinen said annular frame members and engaging the rounding the shaft andcompressed between the,

outer faces of the movable rings and abutments carried by the frame.whereby the movable rings are maintained in snug contact with theimpeller.

13. In a pump, the combination of a shaft, an impeller thereon having atoppositefaces and an annular row' of laterally open buckets Ibeyond saidflat faces, a pair of abutting stationary heads having mating grooves toprovide a passageway about said buckets and intake and exit passages toand from said passageway, a pair of frame members abutting the outersides of said heads and holding them againsteach other,

- bearings carried by said' frame members in which said shaft isjournalled, a pair of movable pressure heads of annular form surroundingthe shaft and contacting with the opposite faces of the impeller closeto the bases of the buckets, and a pair of compression springssurrounding the shaft and compressed between the outer faces of said4movable heads and abutments carried by the two frame membersrespectively.

14. In a pump, the'combination of a vertical frame member having asupporting base and carrying a discharge chamber at the top and hav. ingintermediately a horizontal opening, a pair of mating frame headsmounted in said opening and abutting each other, the opposed faces ofthe heads being grooved to provide an annular passageway with intake anddischarge passages to the exterior ofthe heads, said discharge passagecommunicating with the discharge chamber and there being meansseparating thedischarge passage from the intake passage, a pair of framemembers of cup-shape facing inwardly and abutting the outer faces ofsaid annular frame members, said cup-shaped frame members being boltedto said vertical frame member, the cupshaped frame members carryingbearings f or a drive shaft, a shaft mounted in said bearings, animpeller mounted on the shaft having an annular row of buckets,occupying the annular passageway of said annular frame heads,a pair ofannular sealing rings freely surrounding said shaft and slidably mountedin said frame heads, a pair of compression springs surrounding the shaftand each compressed between the adjacent pressure ring and an inwardlyextending web on the adjacent cup-shaped frame member.

15. In a pump, the combination `of a rotary shaft, an impeller mountedthereon and having smooth opposite faces and an annular row of 'bucketsbeyond the faces, a pair of sleeves embracing the shaft and abuttingopposite sides of g l A buckets travel, a pressure seal continuouslypressed against the side of the impeller, and

f means for adjusting the pressure of said seal.

1 7. In a pump, the combination of a pair of frame members having boresand -grooved inner faces and means for holding the members in faceabutment to define an annular passageway. there being intake and exitpassages communicating with the annular passageway. a shaft atthe axisof said bores, an impeller on said shaft having an annular row ofbuckets adapted to travel in said annular passageway, pressure sealssurrounding the shaft and each including a compression spring and a headbearing against a side of the impeller, said frame members carryingextensions internally threaded about the axisl of the shaft and spacedtherefrom, and externally threaded sleeves occupying such internallythreaded openings and bearing against the outer ends of the pressureseals to force the same against the opposite sides of the impeller.

18. In a pump, the combination of means defining an annular passagewayfor liquid, an im peller having an annular row of buckets operating insaid passageway, a shaft carrying the impeller, a pressure sealsurrounding the shaft and comprising a spring-extended bellowsterminating in an annular member having its outer periphery of nogreater diameter than the inner periphery of the row of buckets andbearing against the impeller, a ring with a cylindrical flange, saidflange surrounding the shaft and occupying the interior of the bellowsand the ring extending across the outer end of the pressure seal, andadjustable means engaging said ring to apply a variable compression tothe spring to adjust the pressure against the impeller.

19. In a pump, the combination of a rotary impeller having an annularrow of buckets, a frame member having in one face an annular ,groove toform a wall for an annular passageway in which the buckets operate. saidframe member having an opening, a sealing head slidably occupyingsaidcopening andA engaging lthe side of the impeller, a yielding memberbetween the outer perimeter of the seal head and the wall of saidopening to prevent liquid passage between them, and means formaintaining the head in contact with the impeller while the latter isrunning.

20. In a pump, the combination of a rotary shaft, an -impeller thereonhaving an annular row of buckets, a stationary frame member` surtlonarymeans providing a raceway V:Ifor the im v peller buckets, admission anddischarge passageways leading fromv said raceway outwardly to the regionbeyond the periphery of said impeller. there being means separating theadmission and discharge passageways,` a pair of annular pressure headsslidably mountedl within said stationary means and engaging the oppositefaces of the maintained inl snug contact with the impeller,

Y impeller, and means for causing said -heads to be l16. In a pump,thecombination 'of'.-rotary 11npeller carrying anV annular row of buckets.means -deflning a passageway' forliquid in which said rounding the shaftand having in one face an annular groove to form a wallfor an annularpassageway in which the buckets operate, said frame member having a boreconcentric of the shaft, a sealing ring slidably occupying said bore andengaging the side of the impeller, there being clearance between theouter periphery of the sealing ring and the bore of the frame member,and a. packing between the outer periphery of the seal head and theinner periphery of the frame member and 'engaging one of suchperipheries whereby the seal head may tip slightly within the stationarymember and maintain an accurate presentation'to the face of theimpeller, and a spring bearing against the outer face of the seal headto maintain such engagement.

Y 21.*In a pump, the combination of stationary frame member defining anannular passageway for liquid, ka shaft. an impeller on the shaft havinganannular vrow `of buckets occupying said eway, aseal head slidablyoccupying space about. the shaft within said frame'member, a

spring bellows surrounding the shaft and bearing against the seal head,a passageway through the stationary member for conveying lubricant tothe space about the pressure seal back of the seal head and a passagewaythrough the seal head for conducting such lubricant from such space tothe face of the seal head engaging the impeller.

22. The combination of a rotary impeller having a row of vanes at itsperiphery providing an annular row of buckets distant from the axis ofthe impeller and means preventing leakage along the face of the impellerfrom buckets containing fluid of lower pressure comprising a sleevelikemember contacting the impeller adjacent the bases of the buckets, andmeans to prevent leakage between said sleevelike member and a memberwith which it frictionally coacts to prevent leakage between them whileallowing relative rotary movement.

23. In a pump, the combination of a rotary impeller having an annularrow of buckets, means dening a passageway in which the buckets traveland means preventing leakage from a bucket containing uid under higherpressure to a bucket containing fluid of lower pressure via the face ofthe impeller, said means including a seal in contact with the face ofthe impeller adjacent the base of the buckets, there being a slippingengagement between the face of the seal and a member of the pump andyielding means comg prising a spring for maintaining such slippingengagement snug during rotation of the impeller.

24. In a pump, the combination of a shaft, a rotary impeller thereonhaving a row of vanes at its periphery providing an annular row ofbuckets distant from the axis of the impeller, a device for preventingleakage from a peripheral region of higher pressure along the face ofthe impeller to a peripheral region of lower pressure comprising asleevelike member surrounding the shaft and contacting the impelleradjacent the bases of the buckets, a compression spring sur rounding theshaft, and an abutment surrounding the shaft and serving to compress thespring against said sleevelike member to maintain the latter member inslipping engagement with a member of the pump between which membersthere is relative rotary movement.

25. In a pump, the combination of a rotary shaft, an impeller thereonhaving an annular row of vanes adjacent its periphery providing bucketsopen at the side of the impeller, said impeller having a smooth sideface between the buckets and axis, means dening a passageway in whichthe vanes travel, a movable sealing member having a smooth face engagingthe side face of the impeller within the circle defining the bottom ofthe buckets, and a yielding pressure device maintaining such sealingmember in contact with the impeller.

26. In a pump, the combination of a drive shaft, an impeller thereonhaving a smooth side face and carrying a row of buckets beyond said faceopen at their outer side, means defining an annular passageway in whichsaid buckets travel, intake and exit passageways communicating with saidannular passageway. a sealing ring contacting with the side face of theimpeller within the circle defining the bases of the buckets close tothe bases oi the buckets, and a compression spring surrounding the shaftand maintaining said sealing ring in slipping contact under pressurewith a member between which there is relative rotary movement.

27. In a pump. the combination of a rotary impeller having vanesproviding an annular row of laterally open buckets, means defining apassageway in which the impeller vanas travel. a seal member engagingthe face of the impeller between its axis and its vanes and having itsouter periphery'adjacent the inner periphery of the buckets, and meanspreventing leakage from said passageway across the perimeter of saidseal member. l

28. In a pump, the combination of means dening an annular passagewaywith intake and exit ports, said means including a frame member with abore, a rotary impeller mounted coaxially with said bore and having anannular row of buckets in said annular passageway and a smooth facebetween the buckets and axis, a round sealing ring slidably mounted insaid bore and having a smooth face, means for maintaining said smoothfaces in actual contact while the impeller ls rotating, and meanspreventing leakage across the periphery of the sealing ring.

29. In a pump, the combination of a frame member having an openingthrough it, one face of said member forming a wall for an annularraceway, a rotary impeller having an annular row of open-sided bucketstraveling in said race- Way, a pressure seal continuously pressedagainst the face of the impeller adiacent the bases of the buckets, across member carried by said frame member and means mounted in the crossmember for adjusting the pressure of the seal against the impeller.

30. In a pump, the combination of a frame member having an openingthrough it, one face of said member forming a wall for an annularraceway. the other face of the member having a projecting annularflange, a rotary shaft, an impeller thereon having an annular row ofbuckets traveling in said raceway, a pressure seal surrounding the shaftwithin said annular iange and engaging the face of the impeller, aspring bearing against the pressure seal, a. stationary cross membercarried by the annular ange and surrounding the shaft, and means on thecross member for compressing the spring to maintain the sealcontinuously pressed against the impeller.

31. The combination of a shaft, an impeller thereon having an annularrow of open-sided buckets adjacent its periphery, means defining anannular passageway for liquid in which said buckets travel, intake anddischarge passages A communicating with said annular passageway, a sealring surrounding the shaft and engaging the, face of the impelleradjacent the bases of the REFERENCES CITED The following'references areof record ln the file of this patent:

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